Generally, a pedal is part of a machine, has the shape of a board operated with the foot, and originates from the Latin language meaning the foot, ‘pedals’. A bicycle transmits power sequentially from a pedal through a large gear and a chain to a driving wheel. Meanwhile, a car is operated by pressing an accelerator pedal, a brake pedal, and a clutch pedal.
As such, the pedal is a manipulating machine part which is used for an accelerator, a brake, or a clutch of a car or various kinds of construction equipment, such as industrial vehicles or fork lift trucks. The pedal is constructed to increase or reduce the operating force according to the strength of pressure applied by the foot, thus controlling the acceleration and the brake or clutch operation of various kinds of operating machines. The pedal is designed to detect the operating state of a machine according to the position of the pedal pressed by pressure.
As industrial transportation equipment, construction equipment, and a car, which are operated by pedals, become highly developed, new control equipment, that is, an Electronic Stability Program (ESP) has been developed to allow a user to operate the equipment or car from the best position while always checking a clutch, a brake, and
an accelerating force according to the speed, the steering angle of a steering wheel, and the operation of the pedals. Thereby, the optimum driving position can be maintained without artificial manipulation. An Electronic Control Unit (ECU) serving as a central brain of the ESP has a central processing control circuit therein, thus automatically manipulating an optimum driving state, based on the data detected by sensors which check the variation in speed, braking operation, clutch operation, variation in temperature, the condition of an engine, the variation in rotation of wheels, and the condition of electronic parts, which affect a vehicle.
ECUs are attached to the four wheels of a car, respectively. When understeer or oversteer of the car occurs, the rotation of the wheels is controlled according to the input program. Thus, even if a driver abruptly manipulates a steering wheel when the car is running, the ECUs function to control the rotation of the four wheels so that the car does not seriously lean or roll over. The ECUs are a technology that is essential to impart intelligence to a car. The ECUs are an important technology for improving a driver's safety and minimizing accidents due to lack of driving experience. The applicable field of the ECUs is gradually expanding, thus the ECUs are being applied to industrial transportation equipment and construction equipment.
As such, among the sensors collecting various data, a Throttle Position Sensor (TPS) for measuring acceleration amount is attached to a throttle body in front of an intake manifold. When an accelerator pedal is pressed, the TPS detects a length corresponding to a pressed amount. The length is measured by a rotary variable resistor which measures a rotating angle according to the variation in opening ratio corresponding to the amount the pedal is pressed, and thus an analogue signal is generated. The TPS determines the engine condition based on the analogue signal and controls the amount of fuel injected.
A sensor using a pedal has a structure similar to that of the TPS. Such a sensor measures the rotating angle of the throttle body which is operated by the pedal and the variation in the operational ratio of the accelerator pedal. However, it is difficult to precisely measure the correlation between the throttle body and the accelerator pedal using the rotary variable resistance sensor, so that it is impossible to correctly control the fuel injection amount.
Further, the sensor using the pedal relatively precisely senses operating parts.
However, it is impossible to precisely measure variation in the operational ratio of the pedal.
Moreover, the rotary variable resistance sensor used to measure the distance the pedal is pressed cannot finely measure the variation in pressure when the pedal moves downwards and upwards, so that it is impossible to sense small motions.